1. Field of the Invention
The present invention pertains to patient interface devices structured to deliver a flow of breathing gas to a patient, and, in particular, to patient interface devices employing adhesives having specific characteristics and in specific configurations to assist in securing the patient interface device to the head of the patient during use in therapy.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube into the patient's esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver positive airway pressure (PAP) therapy to treat certain medical disorders, the most notable of which is OSA. Known PAP therapies include continuous positive airway pressure (CPAP), wherein a constant positive pressure is provided to the airway of the patient in order to splint open the patient's airway, and variable airway pressure, wherein the pressure provided to the airway of the patient is varied with the patient's respiratory cycle. Such therapies are typically provided to the patient at night while the patient is sleeping.
Non-invasive ventilation and pressure support therapies as just described involve the placement of a patient interface device including a mask component having a soft, flexible sealing cushion on the face of the patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal/oral mask that covers the patient's nose and mouth, a nasal cushion that rests beneath the patient's nose (such as a “pillows” style nasal cushion having nasal prongs that are received within the patient's nares or a “cradle” style nasal cushion that rests beneath and covers the patient's nares), or a full face mask that covers the patient's face. Such patient interface devices may also employ other patient contacting components, such as forehead supports, cheek pads and chin pads. The patient interface device is connected to a gas delivery tube or conduit and interfaces the ventilator or pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from the pressure/flow generating device to the airway of the patient. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head.
The headgear typically wraps around the patient's head (coming in contact with the patient's hair and face) in order to apply the necessary forces normal to the face to achieve a suitable seal. This application of a normal force to the face, if too strong, can result in undesirable skin irritations, such as red marks, and/or patient discomfort. Additionally, some mask configurations, such as full face or nasal masks, rely on a flap along the profile of the mask to enable a seal to be achieved along the face. Due to the uniqueness of each person's face, leak paths or mask instability can occur along the mask profile, requiring the patient to use an uncomfortable amount of force.